106 ● Clin Lab Res Den 2014; 20 (2): 106-9

Oral Pathologylinical and Laboratorial Research in Dentistry

in

A simple mandibular bone cyst with remarkable tooth resorption

• Alexandre Viana Frascino Departament of Maxillofacial Surgery, Prosthesis and Traumatology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil • Daniel Martins Departament of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil • José Benedito Dias Lemos Departament of Maxilofacial Surgery, Prosthesis and Traumatology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil • Andrea Mantesso Departament of Stomatology (Discipline of Oral Pathology), School of Dentistry, University of São Paulo, São Paulo, SP, Brazil

This article reports an unusual case of a simple mandibular bone cyst with remarkable tooth resorption

and pain. An 18-year-old woman was referred to our oral and maxillofacial surgery and trauma clinic,

complaining of pain in the left third mandibular molar region. A radiographic exam revealed a well-de-

marcated radiolucent lesion in the left mandible with marked fi rst molar distal root resorption. Based on

the differential diagnoses, an incisional biopsy was performed through a bone window, under local anes-

thesia. Surgical exploration revealed a simple bone cavity fi lled with sanguineous fl uid, with no cyst wall

or tumoral tissue. Histopathological examination revealed thin, fi brous connective tissue with no epithe-

lial coverage and permeated by extensive hemorrhage. Painful symptoms seemed to be caused by a caries

lesion in the adjacent second molar and were resolved by tooth restoration with composite resin. A radio-

graphic postoperative follow-up exam after two months suggests that there was complete bone healing and

that tooth resorption had seemingly ceased. The fi nal diagnosis was a simple bone cyst with unusual tooth

resorption.

Bone Cysts; Tooth Resorption; Surgery, Oral; Pathology, Oral; Diagnosis.

Reabsorção radicular extensa associada a cisto ósseo simples mandibular • Este artigo relata um caso incomum de um cisto

ósseo simples em mandíbula que apresentou reabsorção radicular e dor. Uma paciente do sexo feminino, com 18 anos de idade, foi

encaminhada ao nosso serviço de cirurgia e traumatologia oral e maxilo facial com queixa de dor na região do terceiro molar infe-

rior esquerdo. O exame radiográfi co revelou uma lesão radiolúcida bem delimitada localizada na mandíbula esquerda com reabsorção

acentuada da raiz distal do primeiro molar. Com base nos diagnósticos diferenciais, foi realizada biópsia incisional sob anestesia local

por meio da exposição de uma janela óssea. A exploração cirúrgica da lesão revelou uma cavidade óssea simples preenchida com fl uido

sanguíneo, sem a presença de parede cística ou de tecido tumoral. O exame histopatológico revelou delicado tecido conjuntivo fi broso

sem cobertura epitelial entremeado por extensa hemorragia. Os sintomas dolorosos pareciam ser provenientes de lesão de cárie no

segundo molar. A queixa de dor cessou com a restauração do dente por meio de resina composta. O exame radiográfi co após três meses

de acompanhamento pós-operatório sugere completa reparação óssea e aparente interrupção da reabsorção da raiz dentária. O diag-

nóstico fi nal foi cisto ósseo simples, acompanhado de incomum reabsorção do dente.

Cistos Ósseos; Reabsorção de Dente; Cirurgia Bucal; Patologia Bucal; Diagnóstico.

• Alexandre Viana Frascino Departament of Maxillofacial Surgery, Prosthesis and Traumatology, School of Dentistry, University of São Paulo • Rua Três de Maio, 61, apto. 61 São Paulo, SP, Brazil • 04044 020 E-mail: alexandre.frascino@usp.br

• Received Sep 19, 2013 • Accepted Sep 27, 2013• DOI http://dx.doi.org/10.11606/issn.2357-8041.v20i2p106-109

aBstract |

resuMo |

descrItores |

descrIptors |

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Frascino AV • Martins D • Lemos JBD • Mantesso A •

Clin Lab Res Den 2014; 20 (2): 106-9 ●  107

IntroductIonThe simple bone cyst (SBC), also known as trau-

matic bone cyst, hemorrhagic bone cyst, solitary

bone cyst, and idiopathic bone cavity, was first de-

scribed by Lucas et al. in 1929,1 and was classified

under the name of simple bone cyst in the latest

World Health Organization (WHO) classification

(2005).2 This lesion is described as an intraosseous,

pseudocystic lesion lined with a thin fibrovascular

membrane that is not surrounded by an epithelial

lining, and that is usually either empty or filled

with serous or sanguineous fluid. Radiographical-

ly, it is described as a well-defined, radiolucent le-

sion, surrounded by a thin radiopaque contour. The

presence of scalloped margins extending between

the dental roots is frequently observed. Clinically,

these lesions appear as an empty cavity often filled

with a serous or bloody fluid. Histopathological ex-

amination typically reveals only a tiny connective

tissue sample permeated or not by hemorrhage. Fi-

broblasts and giant cell-like osteoclasts can some-

times be seen. The presence of congested capillary

vessels is uncommon.3 The sites most affected by

SBCs are the long bones (90%), with a high preva-

lence in the metaphyseal region of the humerus

and femur (65% and 25%, respectively). Jawbone

lesions are less common (1%–10%). The mandible

is more commonly affected than the maxilla (4:1),

with a predominance of the molar and premolar re-

gions.4

case reportAn 18-year-old woman was referred to the oral

and maxillofacial surgery and trauma service of

the Luzia de Pinho Melo Clinical Hospital, in Mogi

das Cruzes, São Paulo, Brazil. The patient’s com-

plaint was painless swelling in the left mandible

body. Further inquiries revealed absence of previ-

ous trauma. Extra- and intraoral physical examina-

tions revealed no abnormal findings around the le-

sion. Manual palpation of the swollen area revealed

pain. Painful lymph nodes were nonexistent. The

general health status of the patient was good, and

her family history was noncontributory. Routine

laboratory values were within normal ranges. Ra-

diographic panoramic images exhibited a relatively

well-demarcated, radiolucent, unilocular lesion

with scalloped margins, penetrating among dental

roots associated with the inferior left third molar

(Figure 1). A remarkable resorption of the distal

root of the first molar could be observed. Differ-

ential diagnoses included odontogenic keratocyst,

ameloblastoma, central giant cell lesion, unicystic

ameloblastoma and other cystic lesions.

Lesion exploration through a bone window was

performed under local anesthesia. After vestibular

flap reflection and exposure of the external oblique

ridge, a translucent lesion could be seen through

an extremely thin bony wall. The bony wall mem-

brane-like tissue was detached, and the cystic cav-

ity was opened roughly. The lesion consisted of a

bone cavity with no evidence of a cyst wall or tu-

moral tissue. Moreover, the crown of the left third

molar was found to be impacted. Histopathologi-

Figure 1 | Panoramic radiograph image showing a well-demar-cated, radiolucent, unilocular lesion with scalloped margins in left mandible (yellow dashes). The lesion infiltrates the second molar region and causes a remarkable resorption in the distal root of the first molar. 

A simple mandibular bone cyst with remarkable tooth resorption

108 ● Clin Lab Res Den 2014; 20 (2): 106-9

as part of a group of bone lesions that include the

ossifying fibroma, fibrous dysplasia, central gi-

ant cell lesions, aneurysmatic bone cysts, and

cherubism. Ever since the SBC was first described

by Lucas in 1929,1 medical literature has exten-

sively described the main characteristics and the

recommended management for treating this le-

sion. Most of the cases described have been found

in patients between the age of 20 and 30 years, and

are usually radiolucent unilocular lesions with no

or only slight bone expansion, followed by cortical

thinning. Radiographic images show lesions with

corticated scalloped margins extending between

teeth roots. Rarely can tooth root divergence, bone

cortical loss or root resorption be seen. Generally,

SBCs do not cause cortical bone expansion.4,6,7 Al-

though this case presented with an unusual swell-

ing of the left mandibular body, Martins-Filho et

al. (2012) revised 26 cases of SBC and found bone

expansion only in 8% of cases.

Undoubtedly, the most distinguishing char-

acteristic of the lesion presented was tooth re-

sorption. Nakaoka et al. (2013) reported another

unusual case of a simple mandibular bone cyst

with remarkable tooth resorption presented in a

52-year-old woman.5 However, there are no simi-

lar reports of SBC with noticeable tooth root re-

sorption. Tooth root resorption is a phenomenon

frequently observed in both physiologic and patho-

cal examination showed the presence of a thin and

poorly collagenized tissue, permeated with ex-

tensive hemorrhage. No epithelial lining could be

observed surrounding the lesion. Focal bacterial

colonies could also be observed (Figure 2). This de-

scription is consistent with an SBC.

The postoperative course was uneventful. Post-

operative follow-up after 2 months showed satis-

factory bone healing with partial regression of the

lesion (Figure 3). An accurate pan-radiographic ex-

amination revealed the presence of a caries lesion

in the inferior right second molar. This lesion was

treated successfully with zinc oxide eugenol (ZOE),

and definitive aesthetic restorative treatment was

later performed. To date, no evidence of recurrence

has been recognized.

dIscussIonSBC is a non-neoplastic bone lesion classified as

an intraosseous pseudocyst by the WHO in 2005.2

This lesion may be characterized by the presence

of an osseous asymptomatic cavity with no epithe-

lial lining that is usually an empty space or a space

filled with serous fluid. It is classified by the WHO

Figure 2 | Histopathological micrograph of the excised lesion exhibiting poorly collagenized tissue, bleeding and small fragments of bone.

Figure 3 | Two-month postoperative panoramic radiograph re-veals bone healing. Note the root defect in the left mandibular first molar.

Frascino AV • Martins D • Lemos JBD • Mantesso A •

Clin Lab Res Den 2014; 20 (2): 106-9 ●  109

logic processes. It occurs in primary teeth and

has been reported in association with orthodontic

tooth movements, occlusal traumatism, periodon-

tal disease, periapical granulomas, and reimplant-

ed teeth. Sometimes, a cyst or neoplasm may in-

duce root resorption of the adjacent teeth.2,7,8

In rare cases, SBC have been reported to heal

naturally during the follow-up period.9 However, in

addition to the SBC’s own set of radiographic char-

acteristics, some SBCs are difficult to distinguish

from true cysts, resulting in SBC misdiagnosis and

the patient’s exposure to unnecessary surgical pro-

cedures. The employment of a magnetic resonance

image (MRI), especially dynamic contrast-en-

hanced MRI (DCE-MRI), can provide useful infor-

mation for distinguishing SBCs from other cysts.10

The confounding painful symptom in the pres-

ent case seemed to result from a caries lesion in

the adjacent teeth. This implies that an accurate

physical examination associated with a reliable

image exam evaluation should be performed. The

impacted inferior third molar in the left mandible

was not removed in the surgical exploration, since

it would augment the risk of pathological fracture

from bone loss.

The recurrence rate of SBCs has been described

as greater than 20%, especially in regard to abnor-

mal SBCs.6 However, after a two-month postopera-

tive assessment of the present case, no recurrence

could be observed. Nonetheless, we believe that a

careful, long-term follow-up is recommended for

atypical SBCs, including this case.

conclusIonA simple bone cyst is a frequent lesion, mostly

found in women, between the age of 20 and 40

years. Tooth resorption or other complications re-

lated to these cysts are very rarely observed, and

have been reported to self-resolve in some cases.

This case reported an unusual manifestation of this

pathological entity treated successfully with sur-

gery.

references 1. Lucas CD. Quoted in BLUM, T. Do all cysts of the jaws origi-

nate from the dental system? J Am Dent Assoc. 1929;16:647-

61.

2. Barnes L, Eveson JW, Reichart PA, Sidransky D, editors. Pa-

thology and genetics of head and neck tumours. Lyon, France:

IARC Press; 2005. p. 327.

3. Harnet JC, Lombardi T, Klewansky P, Rieger J, Tempe MH,

Clavert JM. Solitary bone cyst of the jaws: a review of the

etiopathogenic hypotheses. J Oral Maxillofac Surg. 2008

Nov;66(11):2345-8.

4. Kuhmichel A, Bouloux GF. Multifocal traumatic bone cysts:

case report and current thoughts on etiology. J Oral Maxil-

lofac Surg. 2010 Jan;68(1):208-12.

5. Nakaoka K, Yamada H, Horiuchia T, Saito T, Araia G, Kum-

agaia K, et al. A case of simple bone cyst in the mandible with

remarkable tooth resorption. J Oral Maxillofac Surg Med

Pathol. 2013 Jan;25(1):93-6.

6. Martins-Filho PR, Santos T de S, Araújo VL, Santos JS,

Andrade ES, Silva LC. Traumatic bone cyst of the man-

dible: a review of 26 cases. Braz J Otorhinolaryngol. 2012

Apr;78(2):16-21.

7. Harnet JC, Lombardi T, Klewansky P, Rieger J, Tempe MH,

Clavert JM. Solitary bone cyst of the jaws: a review of the

etiopathogenic hypotheses. J Oral Maxillofac Surg. 2008

Nov;66(11):2345-8.

8. Forssell K, Forssell H, Happonen RP, Neva M. Simple bone

cyst. Review of the literature and analysis of 23 cases. Int J

Oral Maxillofac Surg. 1988 Feb;17(1):21-4.

9. Sapp JP, Stark ML. Self-healing traumatic bone cysts. Oral

Surg Oral Med Oral Pathol. 1990 May;69(5):597-602.

10. Yanagi Y, Asaumi J, Unetsubo T, Ashida M, Takenobu T, Hi-

satomi M, et al. Usefulness of MRI and dynamic contrast-

enhanced MRI for differential diagnosis of simple bone cysts

from true cysts in the jaw. Oral Surg Oral Med Oral Pathol

Oral Radiol Endod. 2010 Sep;110(3):364-9.